One of the main demands of modern manufacture which should be satisfied by machines for plastic working, forging machines included, is an ever-increasing production rate. There are known a number of methods of boosting the production rate but regarded as the principal one is the speeding up of dies. Giving extra speed to dies, i.e. increasing the rate of deformation of the workpiece is also a requirement arising in connection with the working of high-alloy steels and alloys deformable with difficulty which gain ground in mechanical engineering, especially in such its fields as aviation, rocket propulsion and the like.
At present, the working speed of the dies of machines for plastic working is decided by a number of factors among which is the circumferential speed of the gears and pinions forming the drive of said machines. In the known forging machines, the rotary motion of the electric motor and drive shaft is transmitted to driven shafts through lay shafts with gears attached thereto. The driven shafts of the eccentric type transform the rotary motion of the drive into a reciprocating or swinging motion of the die. The lay and driven shafts are located in the known machines all the way along the circumference of a circle of a certain diameter and are movably interlinked by means of gears which are attached to these shafts and form a circular train (cf. for example, Pat. No. 1,243,950, B21j of the Federal Republic of Germany). In this drive, the driven shafts are spaced equidistantly apart along the circumference of a circle. In forging machines with four dies, widely used in forge and blanking shops, the driven shafts form a square. As a result, the drive is bulky, occupying a significant floor area in the shop.
In high-speed machines such as, for example, those of the GFM make, Austria, according to Pat. No. 1,243,950 B21j of the Federal Republic of Germany, the circumferential speed of the gears is not over V=.omega.R 20 m/s, where .omega.=.pi.n/30 s.sup.-1 in which n are the revolutions of the driven shaft per minute and R is the radius of the gear in m.
The fact that in the known forging machines the lay and driven shafts are located in a circle of the same diameter, being spaced equidistantly apart, gives rise to circumferential speeds of a magnitude which cannot be endured by the gears of the drive cut by any known method. There is also no way of reducing the resulting vibration and noise to a level consistent with sanitary regulations.
To ensure synchronous operation of all dies, provided the distance between them can be adjusted directly during the forging operation, as this is the case in modern forging machine, the machine according to Pat. No. 1,243,950 of the Federal Republic of Germany employs double slider (Oldham) couplings which link the gears to the driven shafts. The gears of the lay and driven shafts are accommodated in a separate housing. The drive flanges of each Oldham coupling are rigidly attached to the gears and the driven flanges are rigidly attached to flywheels, the gears and flywheels being located in different planes and accommodated in separate housings. The sequence of assembling the gear drive and driven shafts of said forging machines is determined by the design of the machine but, to ensure synchronous operation of the dies, it is necessary to preassemble the gear drive, the Oldham couplings and the driven shafts. On completing said preassembling, keyways are cut in the driven shafts and flywheels in accordance with the marking applied to indicate the position ensuring synchronous operation of the dies.
Said labour-consuming process catering for synchronism of the dies must be repeated each time a driven shaft or flywheel must be renewed due to damage or some other reason which may occur during the period of operation of the machine.
Thus, the gear drive of the forging machine in accordance with Pat. No. 1,243,950 of the Federal Republic of Germany has the following features:
the lay and driven shafts and their gears are located in circles of the same diameter; consequently, the machine is of significant dimensions in plan and the circumferential speed of the gears is excessively high;
synchronous operation of the dies is ensured by means of double slider (Oldham) couplings and a rigid attachment of the flywheels and driven shafts by keys, the gear drive being preassembled and the keyways marked off to that end;
the gears and flywheels are located in different planes, said their position being attributed to the peculiarities of the construction of the machine and its gear drive referred to hereinabove.